Testing?

When you say test the engine.......are you just looking to run the engine, or test the engine and pump by actually riding it. If you just want to test the engine, you should be able to hook it up to your water hose and start and test your engine............on the other hand, if your test includes riding it to see how it responds to throttle and how the pump is working, then no, I have no idea.........................I live way across the desert from you....on a river. Have Fun!

Welcome to seadoo forum!

Let me know what year you are wanting to run. If I remember right, you have the 89 SP.
I'm not so sure about running it wide open for 5 or 10 minutes. Not because it'll overheat, just because you won't have any shaft torque on the engine. To paint a picture for you here; if your PWC is in the water and your running it wide open, the motor is working (pushing water through the jet) causing resistance (shaft torque). Out of the water, it would be like the shaft is freewheeling. If this model is equipped with a rev limiter, then it may be possible. Why do you want to run it wide open out of the water? You should be able to do the standard test's without running wide open.
Personally, I wouldn't run an engine wide open for a prolonged period of time without shaft torque. I may goose it a few times to see that it hits the high ranges for rpm's, but not hold it there. I'm gonna go with a no answer to that question. There are a lot of memebers that run these PWC's, maybe they've done it and can give you a better answer than me.

Manuals!

I see your a premium member, so you've got some of the best technical information at your fingertips for doing just what your looking to do. I haven't gone back in to answer this question in specific, but if you look in the carb section of the manual for your model, you'll find a host of information on tuning and what to look for, i.e., fuel pressure (don't quote me here but if I remember right was about 5 psi. for your model) and syncronizing your carbs to each other and the injection pump, if you haven't already switched over to premix. It discusses the details of your pilot and main jets. How to replace them and set your idle stop screw. Your carb goes through three different ranges of operation, so running wide open isn't necessary to find out if the carbs are tuned. Your ski is actually tuned, if I remember right, at about 1500 rpms in the water or 3000 rpms out.
Let me know if you want to go through the tuning of your carbs. If so, I need your year, model and engine size. If it's still running the standard carbs or if they've been modified. If you feel confident to do it yourself, I'd love to hear how you come out and if you get stuck, give me a shout!....I'm on usually once or twice a day and would love to answer your questions.